CONSTRUCTION OF PERCEPTION STIMULI WITH COPY SYNTHESIS

Yves Laprie & Anne Bonneau
LORIA

A number of experiments in perception requires the construction of speech-like stimuli whose acoustic content needs to be manipulated easily. Formant synthesis offers the possibility of editing all the parameters of speech. However, the construction of stimuli by hand is a very laborious task and therefore automatic tools are necessary. This paper describes two main extensions of a copy synthesis algorithm previously proposed. The first concerns formant tracking which relies on a concurrent curve strategy. The second is a pitch synchronous amplitude adjustment algorithm that enables the capture of fast varying amplitude transitions in consonants. In addition, the automatic determination of the source parameters through the computation of F0 and of the friction to voicing ratio enables the speech signals to be copied automatically. This copy synthesis is evaluated on sentences and V-Stop-V stimuli.